package edu.bbu.commonproject.desktop.gui.view.swing.file.lister.utils;

/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

/*
 * Taken from http://tips4java.wordpress.com/2008/11/06/wrap-layout/ and
 * originally written by Rob Camick.  The About link for the web site at
 * http://tips4java.wordpress.com/about/ says this about IP rights:
 *
 * "You are free to use and/or modify any or all code posted on the Java Tips
 * Weblog without restriction. A credit in the code comments would be nice,
 * but not in any way mandatory."
 */

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Insets;

/**
 * FlowLayout subclass that fully supports wrapping of components.
 */
public class WrapLayout extends FlowLayout
{
	private Dimension	preferredLayoutSize;

	/**
	 * Constructs a new <code>WrapLayout</code> with a left alignment and a
	 * default 5-unit horizontal and vertical gap.
	 */
	public WrapLayout()
	{
		super();
	}

	/**
	 * Constructs a new <code>FlowLayout</code> with the specified alignment and
	 * a default 5-unit horizontal and vertical gap. The value of the alignment
	 * argument must be one of <code>WrapLayout</code>, <code>WrapLayout</code>,
	 * or <code>WrapLayout</code>.
	 * 
	 * @param align
	 *            the alignment value
	 */
	public WrapLayout(int align)
	{
		super(align);
	}

	/**
	 * Creates a new flow layout manager with the indicated alignment and the
	 * indicated horizontal and vertical gaps.
	 * <p>
	 * The value of the alignment argument must be one of
	 * <code>WrapLayout</code>, <code>WrapLayout</code>, or
	 * <code>WrapLayout</code>.
	 * 
	 * @param align
	 *            the alignment value
	 * @param hgap
	 *            the horizontal gap between components
	 * @param vgap
	 *            the vertical gap between components
	 */
	public WrapLayout(int align, int hgap, int vgap)
	{
		super(align, hgap, vgap);
	}

	/**
	 * Layout the components in the Container using the layout logic of the
	 * parent FlowLayout class.
	 * 
	 * @param target
	 *            the Container using this WrapLayout
	 */
	@Override
	public void layoutContainer(Container target)
	{
		Dimension size = preferredLayoutSize(target);

		// When a frame is minimized or maximized the preferred size of the
		// Container is assumed not to change. Therefore we need to force a
		// validate() to make sure that space, if available, is allocated to
		// the panel using a WrapLayout.

		if (size.equals(preferredLayoutSize))
		{
			super.layoutContainer(target);
		}
		else
		{
			preferredLayoutSize = size;
			Container top = target;

			while (top.getParent() != null)
			{
				top = top.getParent();
			}

			top.validate();
		}
	}

	/**
	 * Returns the minimum dimensions needed to layout the <i>visible</i>
	 * components contained in the specified target container.
	 * 
	 * @param target
	 *            the component which needs to be laid out
	 * @return the minimum dimensions to lay out the subcomponents of the
	 *         specified container
	 */
	@Override
	public Dimension minimumLayoutSize(Container target)
	{
		return layoutSize(target, false);
	}

	/**
	 * Returns the preferred dimensions for this layout given the <i>visible</i>
	 * components in the specified target container.
	 * 
	 * @param target
	 *            the component which needs to be laid out
	 * @return the preferred dimensions to lay out the subcomponents of the
	 *         specified container
	 */
	@Override
	public Dimension preferredLayoutSize(Container target)
	{
		return layoutSize(target, true);
	}

	/*
	 * A new row has been completed. Use the dimensions of this row to update
	 * the preferred size for the container.
	 * 
	 * @param dim update the width and height when appropriate
	 * 
	 * @param rowWidth the width of the row to add
	 * 
	 * @param rowHeight the height of the row to add
	 */
	private void addRow(Dimension dim, int rowWidth, int rowHeight)
	{
		dim.width = Math.max(dim.width, rowWidth);

		if (dim.height > 0)
		{
			dim.height += getVgap();
		}

		dim.height += rowHeight;
	}

	/**
	 * Returns the minimum or preferred dimension needed to layout the target
	 * container.
	 * 
	 * @param target
	 *            target to get layout size for
	 * @param preferred
	 *            should preferred size be calculated
	 * @return the dimension to layout the target container
	 */
	private Dimension layoutSize(Container target, boolean preferred)
	{
		synchronized (target.getTreeLock())
		{
			// Each row must fit with the width allocated to the containter.
			// When the container width = 0, the preferred width of the
			// container
			// has not yet been calculated so lets ask for the maximum.

			int targetWidth = target.getSize().width;

			if (targetWidth == 0)
				targetWidth = Integer.MAX_VALUE;

			int hgap = getHgap();
			int vgap = getVgap();
			Insets insets = target.getInsets();
			int horizontalInsetsAndGap = insets.left + insets.right
					+ (hgap * 2);
			int maxWidth = targetWidth - horizontalInsetsAndGap;

			// Fit components into the allowed width

			Dimension dim = new Dimension(0, 0);
			int rowWidth = 0;
			int rowHeight = 0;

			int nmembers = target.getComponentCount();

			for (int i = 0; i < nmembers; i++)
			{
				Component m = target.getComponent(i);
				if (m.isVisible())
				{
					Dimension d = preferred ? m.getPreferredSize() : m
							.getMinimumSize();
					if (rowWidth + d.width > maxWidth)
					{
						// Can't add the component to current row. Start a new
						// row.
						addRow(dim, rowWidth, rowHeight);
						rowWidth = 0;
						rowHeight = 0;
					}
					if (rowWidth != 0)
					{
						// Add a horizontal gap for all components after the
						// first
						rowWidth += hgap;
					}
					rowWidth += d.width;
					rowHeight = Math.max(rowHeight, d.height);
				}
			}

			addRow(dim, rowWidth, rowHeight);

			dim.width += horizontalInsetsAndGap;
			dim.height += insets.top + insets.bottom + vgap * 2;

			// When using a scroll pane or the DecoratedLookAndFeel we need to
			// make sure the preferred size is less than the size of the
			// target containter so shrinking the container size works
			// correctly. Removing the horizontal gap is an easy way to do this.

			dim.width -= (hgap + 1);

			return dim;
		}
	}
}
